In vitro cytotoxicity study of superparamagnetic iron oxide and silica nanoparticles on pneumocyte organelles

Inhalation is the main route of nanoparticles (NP) exposure during manufacturing. Although many mechanisms of toxicity have been described, the interaction of NP with relevant pneumocytes organelles is not widely understood. Considering that the physicochemical properties of NP influence their toxicological responses, the objective of this study was to evaluate whether exposure to different NP, crystalline Fe₃O₄ NP and amorphous SiO₂ NP could alter pneumocytes organelles in alveolar epithelial cells. To achieve this goal, cell viability, ultrastructural changes, lysosomal damage, mitochondrial membrane potential (MMP), lipid droplets (LD) formation and cytokines production were evaluated by MTT, electron microscopy, lysotracker red staining, JC-1, Oil Red staining and Milliplex® assay respectively. Both NP were observed within lamellar bodies (LB), lysosomes, and cytoplasm causing morphological changes. Exposure to SiO₂ NP at 6 h induced lysosomal activation, but not Fe₃O₄ NP. MMP decreased and LD increased at the highest concentrations after both NP exposure. Pro-inflammatory cytokines were released only after SiO₂ NP exposure at 48 h. These results indicate that SiO₂ NP have a greater impact than Fe₃O₄ NP on organelles responsible for energy, secretion, degradation and metabolism in pneumocytes leading to the development of respiratory disorders or the exacerbation of preexisting conditions. Therefore, the established biocompatibility for amorphous NP has to be reconsidered.     

Overestimation of nanoparticles-induced DNA damage determined by the comet assay

The increasing use of engineered nanoparticles (NPs) in a wide range of commercial products raises concern about the possible risks that NPs pose to human health. Many aspects of the interaction between living cells and NPs are still unclear, and a reliable assessment of NP genotoxicity would be important. One of the most common tests used for genotoxicity is the comet assay, a sensitive method measuring DNA damage in individual cells. The assay was originally developed for soluble molecules, but it is also used in the assessment of genotoxicity of NPs. However, concerns have been raised recently about the reliability of this test in the case of NPs, but no conclusive results have been presented. Using nuclei isolated from human epithelial cells incubated with NPs, we obtained clear evidence of overestimation of NP genotoxicity by the comet assay in the case of CeO₂, TiO_2, SiO₂, and polystyrene NPs. Removal of the NPs in the cytoplasm was effective in eliminating this genotoxicity overestimation (ex post damage) and determining the actual damage produced by the NPs during incubation with the cells (ex ante damage). This method could improve significantly the determination of NP genotoxicity in eukaryotic cells.     

Effects of titanium dioxide nanoparticle exposure in Mytilus galloprovincialis gills and digestive gland

Despite the wide use of nanoscale materials in several fields, some aspects of the nanoparticle behavior have to be still investigated. In this work, we faced the aspect of environmental effects of increasing concentrations of TiO₂NPs using the Mytilus galloprovincialis as an animal model and carrying out a multidisciplinary approach to better explain the results. Bioaccumulation suggested that the gills and digestive gland are the most sensitive organs to TiO₂NP exposure. Histological observations have evidenced an altered tissue organization and a consistent infiltration of hemocytes, as a consequence of the immune system activation, even though an increase in lipid peroxidation is uncertain and DNA damage became relevant only at high exposure dose (10?mg/L) or for longer exposure time (96?h). However, the over expression of SOD1 mRNA strengthen the concept that the toxicity of TiO₂NPs could occur indirectly by ROS production. TEM analysis showed the presence of multilamellar bodies, RER fragmentation, and cytoplasmic vacuolization within relevant presence of dense granules, residual bodies, and lipid inclusions. These findings support the evidence of an initial inflammatory response by the cells of the target organs leading to apoptosis. In conclusion, we can state that certainly the exposure to TiO₂NPs has affected our animal model from cellular to molecular levels. Interestingly, the same responses are caused by lower TiO₂NP concentration and longer exposure time as well as higher doses and shorter exposure. We do not know if some of the conditions detected are reversible, then further studies are required to clarify this aspect.     

Influence of agglomeration and specific lung lining lipid/protein interaction on short-term inhalation toxicity

Lung lining fluid is the first biological barrier nanoparticles (NPs) encounter during inhalation. As previous inhalation studies revealed considerable differences between surface functionalized NPs with respect to deposition and toxicity, our aim was to investigate the influence of lipid and/or protein binding on these processes. Thus, we analyzed a set of surface functionalized NPs including different SiO₂ and ZrO₂ in pure phospholipids, CuroSurf^TM and purified native porcine pulmonary surfactant (nS). Lipid binding was surprisingly low for pure phospholipids and only few NPs attracted a minimal lipid corona. Additional presence of hydrophobic surfactant protein (SP) B in CuroSurf^TM promoted lipid binding to NPs functionalized with Amino or PEG residues. The presence of the hydrophilic SP A in nS facilitated lipid binding to all NPs. In line with this the degree of lipid and protein affinities for different surface functionalized SiO₂ NPs in nS followed the same order (SiO₂ Phosphate?～?unmodified SiO₂?<?SiO₂ PEG?<?SiO₂ Amino NPs). Agglomeration and biomolecule interaction of NPs in nS was mainly influenced by surface charge and hydrophobicity. Toxicological differences as observed in short-term inhalation studies (STIS) were mainly influenced by the core composition and/or surface reactivity of NPs. However, agglomeration in lipid media and lipid/protein affinity appeared to play a modulatory role on short-term inhalation toxicity. For instance, lipophilic NPs like ZrO₂, which are interacting with nS to a higher extent, exhibited a far higher lung burden than their hydrophilic counterparts, which deserves further attention to predict or model effects of respirable NPs.     

Effects of silica nanoparticles on isolated rat uterine smooth muscle

In spite of their widespread use, toxicity of silica nanoparticles (SiO₂ NPs) to mammalian has not been extensively investigated. In the present study, it is aimed to investigate the effects and the mechanism of action of 20?nm sized SiO₂ NPs on isolated uterine smooth muscle. A total number of 84 preparations of uterine strips were used in the experiments. Study was designed as four groups: group I (control), group II (0.2?mM SiO₂ NPs), group III (0.4?mM SiO₂ NPs) and group IV (0.8?mM SiO₂ NPs). Spontaneous contractions were recorded using mechanical activity recording system. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and malondialdehyde (MDA) levels were measured using the spectrophotometric methods. Apoptosis of the cells was detected using immunofluorescence staining assay. SiO₂ NP distribution and ultrastructural changes were determined by transmission electron microscopy. In groups II–IV, the frequency of contraction was significantly lower than that of the group I, whereas the contraction energy significantly decreased only in group IV. SOD and GSH-Px activities were significantly lower in experimental groups compared to the control group. MDA level and apoptotic cells were significantly higher in all SiO₂ groups compared to the control group. Numerous SiO₂ NPs in cytoplasm and connective tissue were observed in all dose groups. These findings showed that 20?nm sized SiO₂ NPs enter the connective tissue and cytoplasm of uterine muscle cells and cause oxidative stress and apoptosis leading to impaired uterine contractile activity.     

Silicon dioxide nanoparticle exposure affects small intestine function in an in vitro model

The use of nanomaterials to enhance properties of food and improve delivery of orally administered drugs has become common, but the potential health effects of these ingested nanomaterials remain unknown. The goal of this study is to characterize the properties of silicon dioxide (SiO₂) nanoparticles (NP) that are commonly used in food and food packaging, and to investigate the effects of physiologically realistic doses of SiO₂ NP on gastrointestinal (GI) health and function. In this work, an in vitro model composed of Caco-2 and HT29-MTX co-cultures, which represent absorptive and goblet cells, was used. The model was exposed to well-characterized SiO₂ NP for acute (4?h) and chronic (5?d) time periods. SiO₂ NP exposure significantly affected iron (Fe), zinc (Zn), glucose, and lipid nutrient absorption. Brush border membrane intestinal alkaline phosphatase (IAP) activity was increased in response to nano-SiO₂. The barrier function of the intestinal epithelium, as measured by transepithelial electrical resistance, was significantly decreased in response to chronic exposure. Gene expression and oxidative stress formation analysis showed NP altered the expression levels of nutrient transport proteins, generated reactive oxygen species, and initiated pro-inflammatory signaling. SiO₂ NP exposure damaged the brush border membrane by decreasing the number of intestinal microvilli, which decreased the surface area available for nutrient absorption. SiO₂ NP exposure at physiologically relevant doses ultimately caused adverse outcomes in an in vitro model.     

Cellular interactions of therapeutically delivered nanoparticles

Introduction: Nanoparticles (NPs) are used extensively in drug delivery. They are administered through various routes in the host, and their uptake by the cellular environment has been observed in several pathways. After uptake, NPs interact with cells to different extents, depending on their size, shape, surface properties, ligands tagged to the surface and tumor architecture. Complete understanding of such cellular uptake mechanisms and interactions of NPs is important for their effective use in drug delivery.

Areas covered: This article describes the various cellular pathways for NP uptake, and the factors affecting NP uptake and interactions with cells. Understanding these two important aspects will help in the future design of NPs for effective and targeted drug delivery.

Expert opinion: Surface charge and ligands tagged on the surface of NPs play a critical role in their uptake and interaction with cells; so surface modifications of NPs can offer increased drug delivery effectiveness, for example, the coupling of ligands on the surface of NPs can increase cellular binding, and NPs in biological fluids can be coated with proteins and as such can exert biological effects. All of the factors affecting NP uptake need to be investigated thoroughly before interpreting any NP–cellular interactions.     

Cytotoxicity of silica nanoparticles on HaCaT cells

Despite the widespread use of silica nanoparticles (SiO₂ NPs) in biological and medical fields, their adverse effects have not been clearly elucidated. In this study, spherical SiO₂ NPs with a 50 nm diameter were used to study their interaction with HaCaT cells. SiO₂ NPs were found to be readily internalized into HaCaT cells and localized in the cytoplasm, lysosomes and autophagosomes. Decreased cell viability and damaged cell membrane integrity showed the cytotoxicity of SiO₂ NPs. Significant glutathione depletion and reactive oxygen species generation, which reduced the cellular antioxidant level, could be the major factor of cytotoxicity induced by SiO₂ NPs. Copyright © 2013 John Wiley & Sons, Ltd.     

Toxicity of mixtures of zinc oxide and graphene oxide nanoparticles to aquatic organisms of different trophic level: particles outperform dissolved ions

Concomitant releases of various engineered nanoparticles (NPs) into the environment have resulted in concerns regarding their combined toxicity to aquatic organisms. It is however, still elusive to distinguish the contribution to toxicity of components in NP mixtures. In the present study, we quantitatively evaluated the relative contribution of NPs in their particulate form (NP_(particle)) and of dissolved ions released from NPs (NP_(ion)) to the combined toxicity of binary mixtures of ZnO NPs and graphene oxide nanoplatelets (GO NPs) to three aquatic organisms of different trophic levels, including an alga species (Scenedesmus obliquus), a cladoceran species (Daphnia magna), and a freshwater fish larva (Danio rerio). Our results revealed that the effects of ZnO NPs and GO NPs were additive to S. obliquus and D. magna but antagonistic to D. rerio. The relative contribution to toxicity (RCT) of the mixture components to S. obliquus decreased in the order of RCT_{GO NP(particle)} >?RCT_{ZnO NP(particle)}?>?RCT_{ZnO NP(ion)}, while the RCT of the mixture components to D. magna and D. rerio decreased in the order of RCT_{ZnO NP(particle)}?>?RCT_{GO NP(particle)}?>?RCT_{ZnO NP(ion)}. This finding also implies that the suspended particles rather than the dissolved Zn-ions dictated the combined toxicity of binary mixtures of ZnO NPs and GO NPs to the aquatic organisms of different trophic level. The alleviation of the contribution to toxicity of the ionic form of ZnO NPs was caused by the adsorption of the dissolved ions on GO NPs. Furthermore, the ZnO NP_(particle) and GO NP_(particle) displayed a different contribution to the observed mixture toxicity, dependent on the trophic level of the aquatic organisms tested. The difference of the contributions between the two particulate forms was mainly associated with differences in the intracellular accumulation of reactive oxygen species. Our findings highlight the important role of particles in the ecological impact of multi-nanomaterial systems.     

Dose-dependent cell necrosis induced by silica nanoparticles

In recent years, much attention has been given to nanoparticles (NPs) due to their many possible applications, and as research has progressed, these NPs have become valuable tools for medical purposes. Among many different types of NPs, silica nanoparticles (SiO₂NPs) have been specifically evaluated for medical purposes and have also been used in many different types of products. Although SiO₂NPs have already been applied and are believed to be nontoxic, there is still a concern regarding possible adverse effects that may be triggered after SiO₂NP exposure. Therefore, in the present study, we employed a recommended cell line (BALB/c 3T3) for the toxicity evaluation to investigate the cytotoxic effects of SiO₂NPs produced by chemical synthesis at a laboratory scale. First, we employed OECD guideline 129 in order to evaluate cytotoxicity effects and also estimate the starting doses for acute oral systemic toxicity tests. We evaluated the cytotoxic effects of two types of SiO₂NPs (nonfluorescent and fluorescent) and found that they were not significantly different (IC₅₀ = 1986.39 ± 237 μg/mL and IC₅₀ = 1861.13 ± 186.72 μg/mL, respectively). Then, we used the predicted LD₅₀ of both types of SiO₂NPs to suggest that they could be categorized as GHS category 4 substances. By ultrastructural evaluation, we found that SiO₂NPs are internalized by 3 T3 cells and are located in vacuole-like structures with no other significant changes in cell structure. We also found that SiO₂NPs lead to cell necrosis in a dose-dependent manner.     

Inflammatory response in human alveolar epithelial cells after TiO2 NPs or ZnO NPs exposure: Inhibition of surfactant protein A expression as an indicator for loss of lung function

The increasing use of metal oxide nanoparticles (MONPs) as TiO₂ NPs or ZnO NPs has led to environmental release and human exposure. The respiratory system, effects on lamellar bodies and surfactant protein A (SP-A) of pneumocytes, can be importantly affected. Exposure of human alveolar epithelial cells (A549) induced differential responses; a higher persistence of TiO₂ in cell surface and uptake (measured by Atomic Force Microscopy) and sustained inflammatory response (by means of TNF-α, IL-10, and IL-6 release) and ROS generation were observed, whereas ZnO showed a modest response and low numbers in cell surface. A reduction in SP-A levels at 24 h of exposure to TiO₂ NPs (concentration-dependent) or ZnO NPs (the higher concentration) was also observed, reversed by blocking the inflammatory response (by the inhibition of IL-6). Loss of SP-A represents a relevant target of MONPs-induced inflammatory response that could contribute to cellular damage and loss of lung function.     

Investigating oxidative stress and inflammatory responses elicited by silver nanoparticles using high-throughput reporter genes in HepG2 cells: Effect of size,surface coating,and intracellular uptake

Silver nanoparticles (Ag NP) have been shown to generate reactive oxygen species; however, the association between physicochemical characteristics of nanoparticles and cellular stress responses elicited by exposure has not been elucidated. Here, we examined three key stress-responsive pathways activated by Nrf-2/ARE, NFκB, and AP1 during exposure to Ag NP of two distinct sizes (10 and 75 nm) and coatings (citrate and polyvinylpyrrolidone), as well as silver nitrate (AgNO₃), and CeO₂ nanoparticles. The in vitro assays assessed the cellular response in a battery of stable luciferase-reporter HepG2 cell lines. We further assessed the impact of Ag NP and AgNO₃ exposure on cellular redox status by measuring glutathione depletion. Lastly, we determined intracellular Ag concentration by inductively coupled plasma mass spectroscopy (ICP-MS) and re-analyzed reporter-gene data using these values to estimate the relative potencies of the Ag NPs and AgNO₃. Our results show activation of all three stress response pathways, with Nrf-2/ARE displaying the strongest response elicited by each Ag NP and AgNO₃ evaluated here. The smaller (10-nm) Ag NPs were more potent than the larger (75-nm) Ag NPs in each stress-response pathway, and citrate-coated Ag NPs had higher intracellular silver concentrations compared with both PVP-coated Ag NP and AgNO₃. The cellular stress response profiles after Ag NP exposure were similar to that of AgNO₃, suggesting that the oxidative stress and inflammatory effects of Ag NP are likely due to the cytotoxicity of silver ions.     

Impact of lithiated cobalt oxide and phosphate nanoparticles on rainbow trout gill epithelial cells

Abstract

Metal oxide and phosphate nanoparticles (NPs) are ubiquitous in emerging applications, ranging from energy storage to catalysis. Cobalt-containing NPs are particularly important, where their widespread use raises questions about the relationship between composition, structure, and potential for environmental impacts. To address this gap, we investigated the effects of lithiated metal oxide and phosphate NPs on rainbow trout gill epithelial cells, a model for environmental exposure. Lithium cobalt oxide (LCO) NPs significantly reduced cell viability at10?µg/mL, while a 10-fold higher concentration of lithiated cobalt hydroxyphosphate (LCP) NPs was required to significantly reduce viability. Exposure to Li⁺ and Co²⁺ alone, at concentrations relevant to ion released from the NPs, did not reduce cell viability and minimally impacted reactive oxygen species (ROS) levels. Both LCO- and LCP-NPs were found within membrane-bound organelles. However, only LCP-NPs underwent rapid and complete dissolution in artificial lysosomal fluid. Unlike LCP-NPs, LCO-NPs significantly increased intracellular ROS, could be found within abnormal multilamellar bodies, and induced formation of intracellular vacuoles. Increased p53 gene expression, measured in individual cells, was observed at sub-toxic concentrations of both LCO- and LCP-NPs, implicating both in inductions of cellular damage and stress at concentrations approaching predicted environmental levels. Our results implicate the intact NP, not the dissolved ions, in the observed adverse effects and show that LCO-NPs significantly impact cell viability accompanied by increase in intracellular ROS and formation of organelles indicative of cell stress, while LCP-NPs have minimal adverse effects, possibly due to their rapid dissolution in acidic organelles.     

The effect of TiO(2) and Ag nanoparticles on reproduction and development of Drosophila melanogaster and CD-1 mice

In the last two decades, nanoparticles (NPs) have found applications in a wide variety of consumer goods. Titanium dioxide (TiO₂) and silver (Ag) NPs are both found in cosmetics and foods, but their increasing use is of concern due to their ability to be taken up by biological systems. While there are some reports of TiO₂ and Ag NPs affecting complex organisms, their effects on reproduction and development have been largely understudied. Here, the effects of orally administered TiO₂ or Ag NPs on reproduction and development in two different model organisms were investigated. TiO₂ NPs reduced the developmental success of CD-1 mice after a single oral dose of 100 or 1000 mg/kg to dams, resulting in a statistically significant increase in fetal deformities and mortality. Similarly, TiO₂ NP addition to food led to a significant progeny loss in the fruit fly, Drosophila, as shown by a decline in female fecundity. Ag NP administration resulted in an increase in the mortality of fetal mice. Similarly in Drosophila, Ag NP feeding led to a significant decrease in developmental success, but unlike TiO₂ NP treatment, there was no decline in fecundity. The distinct response associated with each type of NP likely reflects differences in NP administration as well as the biology of the particular model. Taken together, however, this study warns that these common NPs could be detrimental to the reproductive and developmental health of both invertebrates and vertebrates.     

Contact-dependent transfer of TiO2 nanoparticles between mammalian cells

Cellular organelles have been shown to shuttle between cells in co-culture. We hereby show that titanium dioxide (TiO₂) nanoparticles (NPs) can be transferred in such a manner, between cells in direct contact, along with endosomes and lysosomes. A co-culture system was employed for this purpose and the NP transfer was observed in mammalian cells including normal rat kidney (NRK) and HeLa cells. We found that the small GTPase Arf6 facilitates the intercellular transfer of smaller NPs and agglomerates. Spherical, anatase nano-TiO₂ with sizes of 5 (Ti5) and 40?nm (Ti40) were used in this study. Humans are increasingly exposed to TiO₂ NPs from external sources such as constituents of foods, cosmetics, and pharmaceuticals, or from internal sources represented by Ti-based implants, which release NPs upon abrasion. Exposure to 5?mg/l of Ti5 and Ti40 for 24?h did not affect cellular viability but modified their ability to communicate with surrounding cells. Altogether, our results have important implications for the design of nanomedicines, drug delivery and toxicity.     

Cytotoxicity and genotoxicity of silver nanoparticles in the human lung cancer cell line,A549

Nanomaterials, especially silver nanoparticles (Ag NPs), are used in a rapidly increasing number of commercial products. Accordingly, the hazards associated with human exposure to nanomaterials should be investigated to facilitate the risk assessment process. A potential route of exposure to NPs is through the respiratory system. In the present study, we investigated the effects of well-characterized PVP-coated Ag NPs and silver ions (Ag+) in the human, alveolar cell line, A549. Dose-dependent cellular toxicity caused by Ag NPs and Ag+ was demonstrated by the MTT and annexin V/propidium iodide assays, and evidence of Ag NP uptake could be measured indirectly by atomic absorption spectroscopy and flow cytometry. The cytotoxicity of both silver compounds was greatly decreased by pretreatment with the antioxidant, N-acetyl-cysteine, and a strong correlation between the levels of reactive oxygen species (ROS) and mitochondrial damage (r _s = −0.8810; p = 0.0039) or early apoptosis (r _s = 0.8857; p = 0.0188) was observed. DNA damage induced by ROS was detected as an increase in bulky DNA adducts by ³²P postlabeling after Ag NP exposure. The level of bulky DNA adducts was strongly correlated with the cellular ROS levels (r _s = 0.8810, p = 0.0039) and could be inhibited by antioxidant pretreatment, suggesting Ag NPs as a mediator of ROS-induced genotoxicity.     

CeO2 nanoparticles alter the outcome of species interactions

Despite considerable research on the environmental impacts of nanomaterials, we know little about how they influence interactions between species. Here, we investigated the acute (12 d) and chronic (64 d) toxicities of cerium oxide nanoparticles (CeO₂ NPs) and bulk particles (0–200?mg/L) to three ciliated protist species (Loxocephalus sp., Paramecium aurelia, and Tetrahymena pyriformis) in single-, bi-, and multispecies microcosms. The results show that CeO₂ NPs strongly affected the interactions between ciliated protozoan species. When exposed to the highest CeO₂ NPs (200?mg/L), the intrinsic growth rates of Loxocephalus and Paramecium were significantly decreased by 18.87% and 88.27%, respectively, while their carrying capacities declined by more than 90%. However, CeO₂ NP exposure made it difficult to predict outcomes of interspecific competition between species. At higher NP exposure (100 and 200?mg/L), competition led to the extinction of both species in the Loxocephalus and Paramecium microcosms that survived in the absence of competitors or CeO₂ NPs. Further, the presence of potential competitors improved the survival of Loxocephalus to hundreds of individuals per milliliter in microcosms with Tetrahymena where Loxocephalus would otherwise not be able to tolerate high levels of NP exposure. This result could be attributed to weakened NP adsorption on the cell surface due to competitor-caused reduction of NP surface charge (from ?18.52 to ?25.17?mV) and intensified NP aggregation via phagocytosis of NPs by ciliate cells. Our results emphasize the need to explicitly consider species interactions for a more comprehensive understanding of the ecological consequences of NP exposure.     

Limit-test toxicity screening of selected inorganic nanoparticles to the earthworm Eisenia fetida

The toxicity of a range of inorganic (Ag, Cu, Ni, Al₂O₃, SiO₂, TiO₂ and ZrO₂) nanoparticles (NP) and their corresponding metal salt or bulk metal oxide were screened for toxicity toward the earthworm Eisenia fetida using the limit-test design (1000 mg/kg). This study provides the first ecotoxicological life history trait data on earthworms for each these NPs, as well as for AgNO₃, Al₂O₃, SiO₂, TiO₂ and ZrO₂. Significant effects were observed on survival for AgNO₃ (2.5% of controls), CuCl₂ (17.5% of controls) and NiCl₂ (32.5% of controls) and on reproduction (AgNO₃, CuCl₂, NiCl₂, Ag-NP, Cu-NP, TiO₂-NP); with total reproductive failure in both silver treatments. Ag-NP, Cu-NP and TiO₂-NP were the only NPs that caused toxic effects to E. fetida. The toxicity could not be singularly related to particle size or zeta potential or to the inherent element constituting the NPs (e.g. Ag).     

A comparative study on the in vitro cytotoxic responses of two mammalian cell types to fullerenes,carbon nanotubes and iron oxide nanoparticles

The present study was designed to evaluate and compare the time- and dose-dependent cellular response of human periodontal ligament fibroblasts (hPDLFs), and mouse dermal fibroblasts (mDFs) to three different types of nanoparticles (NPs); fullerenes (C₆₀), single walled carbon nanotubes (SWCNTs) and iron (II,III) oxide (Fe₃O₄) nanoparticles via in vitro toxicity methods, and impedance based biosensor system. NPs were characterized according to their morphology, structure, surface area, particle size distribution and zeta potential by using transmission electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller, dynamic light scattering and zeta sizer analyses. The Mössbauer spectroscopy was used in order to magnetically characterize the Fe₃O₄ NPs. The hPDLFs and mDFs were exposed to different concentrations of the NPs (0.1, 1, 10, 50 and 100?μg/mL) for predetermined time intervals (6, 24 and 48?h) under controlled conditions. Subsequently, NP exposed cells were tested for viability, membrane leakage and generation of intracellular reactive oxygen species. Additional to in vitro cytotoxicity assays, the cellular responses to selected NPs were determined in real time using an impedance based biosensor system. Taken together, information obtained from all experiments suggests that toxicity of the selected NPs is cell type, concentration and time dependent.     

The effects of endoplasmic reticulum stress inducer thapsigargin on the toxicity of ZnO or TiO2 nanoparticles to human endothelial cells

It was recently shown that ZnO nanoparticles (NPs) could induce endoplasmic reticulum (ER) stress in human umbilical vein endothelial cells (HUVECs). If ER stress is associated the toxicity of ZnO NPs, the presence of ER stress inducer thapsigargin (TG) should alter the response of HUVECs to ZnO NP exposure. In this study, we addressed this issue by assessing cytotoxicity, oxidative stress and inflammatory responses in ZnO NP exposed HUVECs with or without the presence of TG. Moreover, TiO₂ NPs were used to compare the effects. Exposure to 32?μg/mL ZnO NPs (p?2 NPs (p?>?0.05), significantly induced cytotoxicity as assessed by WST-1 and neutral red uptake assay, as well as intracellular ROS. ZnO NPs dose-dependently increased the accumulation of intracellular Zn ions, and ZnSO₄ induced similar cytotoxic effects as ZnO NPs, which indicated a role of Zn ions. The release of inflammatory proteins tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) or the adhesion of THP-1 monocytes to HUVECs was not significantly affected by ZnO or TiO₂ NP exposure (p?>?0.05). The presence of 250?nM TG significantly induced cytotoxicity, release of IL-6 and THP-1 monocyte adhesion (p?p?>?0.05). ANOVA analysis indicated no interaction between exposure to ZnO NPs and the presence of TG on almost all the endpoints (p?>?0.05) except neutral red uptake assay (p?相似文献